CN1275411C - Method and devices for operating a radio-based telecommunications system - Google Patents

Abstract

The present invention discloses a method and apparatus for operating a wireless telecommunication system according to a first power value defined by, preferably a radio network controller (CRNC), or comprising at least The parameter of the second power value of the average value of the transmission power of the data in the two frames is used to calculate the virtual reference power setting or transform the transmission identifier power of the TFCI identifier bit. The virtual reference power may be a fixed power value sent by the radio network controller or a hard-coded value stored in the base station. The advantage of this method is that the power of the TFCI and the pilot can be calculated very conveniently by adjusting the power of the TFCI and the pilot to the virtual reference power in the same manner as the usual practice in terms of data bit power.

Description

Method for operating a wireless telecommunications system

technical field

The present invention relates to a method and an apparatus or set of apparatus for operating a wireless telecommunication system in which data is transmitted on the downlink from a radio base station controlled by a radio network controller to mobile subscribers using a common physical channel A device where data is sent in frame slots. In particular, but not limited to, the invention relates to the calculation of the transmit power of a signal to be transmitted on a common physical channel known as secondary Common Control Physical Channel ( ), UMTS is a CDMA wireless telecommunication system defined by 3GPP (Third Generation Collaboration Project Organization) in ETSI (European Telecommunications Standards Institute).

Background technique

The known Supplementary Common Control Physical Channel (S-CCPCH) is a physical common channel on the downlink that can basically carry two transport channels, namely the paging channel (PCH) and the forward access channel (FACH: forward access channel). . Therefore, the S-CCPCH is used for paging and for transmitting signaling bits or very small amounts of data. There may be one or several S-CCPCHs on this physical channel for traffic load in each cell with different total bit rates.

The S-CCPCH is a physical channel consisting of a frame subdivided into time slots, each time slot having a data field for inserting useful data bits, ie data bits of the transport channels PCH and/or FACH. Thus, the S-CCPCH can carry zero or one PCH transport channel and zero, one or several FACH transport channels. The different combinations of transport channels are called TFCs (Transport Format Combinations). Possible TFC also includes the situation that there is no data transmission in the S-CCPCH temporarily. In order to identify the TFC used, a so-called TFCI (TFC Identification) is defined, which is a number that identifies the TFC used.

The TFCI bits are transmitted within a region in the slot of the S-CCPCH frame so that all mobile stations within the radio cell, ie user equipment (UE), can know the currently used TFC.

In addition, there are so-called pilot bits inserted in another area of the time slot, these pilot bits appear in the form of bits and are used to form pilot signal.

At the transmitting end, ie at the base station, the transmit power value to be used for data bit transmission on the S-CCPCH is controlled by a radio network controller (RNC) connected to the base station. The transmit power for the TFCI bits and pilot bits, which may be different, is also controlled by the RNC by adjusting these powers relative to the power of the currently used S-CCPCH data bits.

Contents of the invention

A problem arises when no data, ie neither PCH data nor FACH data, is transmitted in the S-CCPCH frame. Indeed, in this case no transmit power value is defined for the S-CCPCH data bits. Therefore, known adjustment methods of TFCI and pilot power cannot be used.

Thus, the TFCI identifies TFCs that are inactive and that there is a problem to be resolved if no data is sent. Although the TFCI bits must be reliably received at the receiving mobile station in order to decode correctly and detect the TFCI correctly, in this case the TFCI power cannot be calculated. Correct detection of TFCI will not only help the mobile station to know the free data area, but also will allow the mobile station to switch to sleep mode to save power.

The solutions to all problems are defined by the claims according to the present invention. Therefore, it is proposed to set or change the transmit identifier power of the TFCI identifier bits by adding a specific offset to the virtual reference power calculated or It is obtained by averaging the power values that have been used for previous frames. The virtual reference power can also be a fixed power value sent by the radio network controller or a hard-coded value stored in the base station.

The advantage of this proposed method is that the TFCI and pilot values are conveniently calculated in the same way as is usually done by adding a specific offset to the virtual reference power when no data is transmitted. power.

Other advantages will be obtained from the more specific features defined in the dependent claims, which will also be presented by the preferred embodiments described in more detail later.

Therefore, each time slot of the frame also has an area for carrying pilot bits, and the pilot frequency is a training sequence used to optimize reception in the common physical channel. The step of adding a specific offset to the data power of the pilot bit to set the transmit pilot power of the pilot bit. When no data is to be sent, the step of setting the transmit pilot power of the pilot bits by adding a specific offset to the virtual reference power.

In this aspect, a further feature is to cause each of the transmitted identifier power and/or the transmitted pilot power to correspond to a virtual reference power by adding a respective offset power to said virtual reference power.

Another additional feature is that each of the transmit identifier power and/or transmit pilot corresponds to said virtual reference power and to said transmit data power by adding the same respective offset power.

Furthermore, the parameter may be a predetermined maximum power value that will not be exceeded in the transmission channel.

In this regard, one of the parameters may be the maximum pilot channel power that will not be exceeded in each transport channel, and the other may be the maximum forward access channel power that will not be exceeded in each transport channel .

Another feature may be added that the reference power is calculated by selecting the lowest power value from at least two maximum power values that have been used or are currently being used in the transmission channel.

In addition, the reference power is calculated from an average power value obtained from at least two maximum power values being used in the transmission channel.

Description of drawings

The invention and the advantages obtained therefrom will be described in detail by showing preferred embodiments and with reference to the following drawings.

Fig. 1 shows a schematic structural diagram of a wireless telecommunication system;

Figure 2 shows the structure of a common physical channel and its subdivision into frame slots;

Figure 3 shows a table of allowed transport format combinations;

Fig. 4 shows that if there is no data transmission, the value transmit power value is located in the part of the common physical channel;

Figure 5 shows an excerpt of a sequence of frames; and

Figure 6 shows the parameters sent from the radio network controller to the base station.

Detailed ways

In FIG. 1 is shown a schematic structural view of a wireless telecommunication system with at least one radio network controller CRNC for controlling several base stations NB, also called Node Bs, one of which is shown in FIG. 1 as an example. Each base station NB provides radio service to several mobile user equipments UE, one of which is shown in FIG. 1 as an example. Among other physical channels a so-called Secondary Common Physical Channel SCCPCH is used, which is a downlink for transmitting information and data from the base station NB to the individual user equipment UE. Basically, SCCPCH is used to carry different transport channels, namely paging channel PCH and one or more forward access channels, such as FACH1 and FACH2, as shown in FIG. 1 . This is just an example of what constitutes the SCCPCH. Combinations of other transport channels are also possible, especially FACH and PCH. The structure of the SCCPCH and the transmission mode used will be clearer when referring to FIG. 2 .

As shown in FIG. 2, the frame structure of the SCCPCH structure, the transmission on the physical channel is performed by sending radio frames RFk, RFk+1 and so on. Each frame has a certain number of slots, eg 15 slots S0, S1 to S14. In each time slot, eg Si, there are transmitted data bits in a specific data area DAT. Likewise, the identifier bits are sent in the field TFCI and the pilot bits are sent in the pilot data field PLT. In addition to the TFCI bits, pilot bits may be sent, or no pilot bits at all may be sent. The area DAT is used for the transmission of useful data bits via the aforementioned transport channels PCH, FACH1 and FACH2. The DAT area is the second area in each time slot, while the first area is allocated to carry the bits of the identifier TFCI, a so-called Transport Format Combination Identifier, giving information about the content in the DAT area.

In particular, depending on which combination is used, the TFCI identifies the use of DAT regions to carry transport channel bits. This combination of so-called Transport Format Combinations TFCs transforms the frame into a frame as shown in FIG. 3 .

As an example, it is shown that the first radio frame RFk carries the PCH bit and the FACH1 bit, and the subsequent next radio frame RFk+1 is dedicated to carrying the FACH1 bit. The next frame RFk+2 is dedicated to carrying PCH bits, and the subsequent frame RFk+3 does not carry data bits at all. Afterwards, frame RFk+4 carries data again, that is, PCH bits and FACH2 bits. And the next frame RFk+4 carries various data bits, namely PCH, FACH1 and FACH2 bits. On the contrary, the subsequent frame RFk+6 carries no data like the frame RFk+3. This is just one example of TFC. Other combinations are also possible. The TFC shown in Figure 3 defines the type of transport channel being used. In addition, the TFC can also define the number and size of transport blocks or similar parameters for each transport channel.

The transport format combination TFC can transform the frame into a frame as shown in FIG. 3 . There may also be combinations of carrying two FACH bits, as shown in the example in frame RFk+n.

The inactive TFCs in the frame are identified by a TFCI with a value identifying the inactive combination from a different combination of transport channels. The TFCI also has a value indicating whether no data is sent in the frame.

Returning to Figure 2, each region of the time slot, ie TFCI, DAT and PLT, is shown, each region having a separate value transmit power value. The transmit power DATPWR of the DAT area is set according to the parameters given by the radio network controller (see Fig. 1 CRNC) for those transport channel bits (PCH bits or FACH bits) inserted in the current DAT area.

This means that when PCH is inserted into DAT area, CRNC gives predetermined PCH power for setting power value DATPWR. In other cases, when inserting FACH bits, then the CRNC gives the so-called MAXFACHPWR. This means that when the DAT area is filled with useful data from the transport channel, the transmit power DATPWR is set to the values that depend on these parameters given by the CRNC.

Starting from the power value DATPWR, the power values of the other areas, namely the TFCI and PLT areas, are adjusted by adding a specific power offset PO1 or PO3 respectively, resulting in different settings for the power applied in each area within the time slot.

That situation creates problems when no data is sent at all. This means that if the transport format combination TFC currently used in a different radio frame (eg RFk+3 or RFk+6 of FIG. 3 ) has a free DAT area, the specific power value DATPWR is not set at all. Therefore, the adjustment method for TFCI and PLT power cannot be applied.

According to the invention, it is proposed to introduce a virtual reference power in these specific cases when no data is sent. It is also possible that no TFCI and/or pilot bits are sent at all. The principles of the present invention will become clearer from the following description of FIGS. 4 to 6 .

FIG. 4 shows a time slot with a first area TFCI and a second area inserted with data and a third area inserted with pilot bits, but no data is displayed in the data area. According to the invention it is possible to calculate the reference power REFPWR, which is a virtual value derived from a parameter defined by the radio network controller or derived from a power value representing the average value of the transmit power that has been used for previous frames. Then, after calculating the virtual reference value REFPWR, other power values for the TFCI and PLT regions can be conveniently set by adding the respective power offset PO1 or PO3.

As shown in Fig. 5, according to the method of the present invention, a series of transmitted radio frames are obtained, such as RFk-2, RFk-1, RFk, etc., no matter whether data is transmitted or not, each frame has a given value for TFCI and PLT bits. power value.

This method has the effect that at the receiving end, i.e. at the user mobile equipment (see Figure 1 UE), the TFCI can always be received with a received value sufficient for reliable detection of the identifier and reliable demodulation and decoding of the received information bits identifier and PLT signal. For TFCI in particular, this means that the TFCI bits can always be received exactly even when no data is being sent, thereby identifying the currently used transport format combination TFC. This effect cannot be controlled by

prior art systems.

Furthermore, the proposed method has the advantage that in both cases, i.e. when data is transmitted and when no data is transmitted, it is always possible to obtain the results for TFCI and Specific power values for PLT regions.

Fig. 6 shows a schematic diagram of the transmission parameters sent from the radio network controller CRNC to the base station NB for forming the virtual reference power without data transmission. These parameters specifically include: the standby paging power value PCHWR for the paging bit, and the maximum power values MAXFACHPWR1 and MAXFACHPWR2 for defining the maximum power value to be used on the forward access channel. All parameters are sent in a protocol called NBAP. Therefore, these parameters are also called NBAP parameters NBAPPAR. One way to form a virtual reference power (see REFPWR in Figure 4) is to use these parameters and calculate the reference power from them. Another method is to form the reference power from the average power value obtained from previously transmitted frames. This means, referring to Fig. 4, that the virtual reference power for the current frame RFk is calculated by averaging those power values which have been used for the previous frames RFk-1 and RFk-2. Preferably, the calculation of the reference power only considers the data bit power of previous frames. Determining whether to generate an average value from at least two frames in a fraction of previous frames or from the last frame to obtain an average value is only a matter of implementation. Preferably, the calculation of the reference power only considers the data bit power of previous frames.

The described invention is especially applicable to the so-called UMTS (Universal Mobile Telecommunications System), but is not exclusive of application to other wireless telecommunications systems.

Claims (8)

1. the method for an operating radio telecommunication system, wherein public physic channel is used for sending data from the wireless base station by radio network controller control to mobile subscriber equipment on down link, wherein these data send with frame slot, each frame is represented the combination of transmission channel, and each time slot of frame has the zone that is used to carry described data bit and has the zone that is used for bearing identification symbol position, described identifier identifies the combination of the described transmission channel that uses in the described frame, and whether described identifier also identifies does not have data to be sent out in the described frame, this method comprises the steps:

When having data to be sent out in the frame,, the transmit identification symbol power of identifier bit is set by on the data power of data bit, adding specific skew;

Perhaps when not having data to be sent out in the frame, by on virtual reference power, adding specific skew, the transmit identification symbol power of described identifier is set, virtual reference power is according to by wireless network components, and especially the calculation of parameter that limits of radio network controller obtains or the performance number of the frame that is used for the front is averaged acquisition.

2. method according to claim 1, wherein each time slot of frame also has the zone that is used to carry pilot bit, and described pilot tone is to be used to optimize the training sequence that described public physic channel receives, and this method also comprises the steps:

Be sent out as data, then, the emission pilot power of pilot bit be set by on the described data power of data bit, adding specific skew;

And, then, the emission pilot power of described pilot bit is set by on described virtual reference power, adding specific skew when free of data is sent out.

3. method according to claim 2, wherein by add power excursion separately on virtual reference power, each power in described transmit identification symbol power and/or the emission pilot power is corresponding with described virtual reference power.

4. method according to claim 3 wherein by adding identical power excursion separately, makes each power in transmit identification symbol power and/or the emission pilot power corresponding with described virtual reference power and described emission data power.

5. method according to claim 1, wherein said parameter are the predetermined maximum power values that can not be exceeded in the transmission channel.

6. method according to claim 5, a power in the wherein said parameter is paging channel power, and wherein at least another power be the maximum forward access channel power that can not be exceeded in each forward access channel.

7. method according to claim 5, wherein reference power calculates by selecting the lowest power value in that use or that using always described two maximum power values from transmission channel at least.

8. method according to claim 5, wherein described at least two maximum power values of using from transmission channel of reference power obtain average power content and calculate.

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